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  <title>Document</title>
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<script>
  //函数也是一种数据类型
//function fn(){
//}
//funtion 数据类型-->对象（数组，函数）
//coonsole.log(typeof fn)
function f1(s){
  //var k=12345;
  //console.log(k);
  s();
}
var f2=function(){
  console.log(2222);
}
//f2函数会被当做值，传入f1函数内
f1(f2);
</script>
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</body>
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